<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    请输入星期几 <input class="one" type="text">
    <button class="tow">查看今日餐品</button>
    <script>
        var one=document.getElementsByClassName("one")[0]
        var tow=document.getElementsByClassName("tow")[0]
        tow.onclick=function(){
       var box=one.value;
       if(box==1 || box==3){
        alert("今天吃宫保鸡丁");
       }else if(box==2){
alert("今天吃肉末茄子");
       }else if(box==4 || box==5){
        alert("今天吃番茄炒鸡蛋");
       }else if(box==6){
        alert("呜呜呜，没钱了吃不起了");
       }

        }
    </script>
</body>
</html>